1. Baarle-Hertog/Baarle-Nassau

On the border of Belgium and the Netherlands lie two towns that are — quite literally — inextricably linked. The Belgian town of Baarle-Hertog and the Dutch town of Baarle-Nassau are essentially one town comprising a series of enclaves (that is, territory belonging to one governing body surrounded by land belonging to another governing body), meaning that some pockets of the town are Belgian and some pockets are Dutch (see map below). The borders are marked by a series of white plus signs drawn through the streets, with B and NL indicating which country is on which side. The borders go right through homes, restaurants, and more. Why did this mess happen? It goes back to a series of complex land agreements in medieval times.

2. Jungholz, Austria/Germany

There are two ways of moving from the Lech valley to the Jungholz valley in the Austrian Tyrol: you either put on your hiking boats and climb up and over Mount Sorgschrofen (5,364ft), or you drive around via Germany.

And to do the climb without straying accidentally across the border is hard, because this 'quadripoint' comes to a precise pinch point, painted on a rock.

Once down the other side, Jungholz itself seems like a quiet agricultural community, but its herniated topography provides a loophole in German banking regulations, so private banks have registered offices here.

3. Hotel Arbez, France/Switzerland

Anyone who has been through border-hugging Geneva airport will know that it has different exits depending on whether you want France or Switzerland. This hotel around five miles to the north of that airport takes the border-squatting principle a step further, sitting right on top of the line, so its dining room, kitchen etc are actually bisected.

Back in 1862 a local businessman got wind of a treaty modifying the border and created the building to straddle the new route before it was ratified.

4. Lake Constance, Austria/Switzerland/Germany

German is the lingua franca around the third-largest lake in central Europe, but on the question of watery jurisdiction all three nations agree to disagree. The borders of Austria, Switzerland and Germany arrive with precision at the lakeshore, only to dissolve when they hit the water. No treaty agreement has ever been reached dividing the lake, so specific local issues such as fishing rights and boat licensing have to be settled by individual agreements.

5. Kaliningrad, Poland/Russia

This relic of Russian imperialism looms rather threateningly on the far side of the Bay of Gdansk. The enclave of Kaliningrad is what remains after Lithuania, Latvia and Estonia all declared independence from the Soviet Union, leaving it marooned from the motherland.

In the early 20th century this was Germany’s Königsberg, but it was renamed and forcibly repopulated after World War II, and today its strategic position means that it is heavy with military installations.

According to www.mirror.co.uk. Source of photo: internet